The Crimson Cog are a historical re-enactment group in New South Wales. They focus on the Hanseatic League in the years 1250-1300, particularly the city of Lübeck in northern Germany. The Hanseatic League were a confederation of merchant guilds and towns who dominated trade in the Baltic and North Seas from the thirteenth to sixteenth centuries. The Cog was a cargo ship used by the League.
For their website see http://crimsoncog.wix.com/crimson-cog